1. Field of the Invention
The present invention relates to an optical device and a method for manufacturing it.
2. Prior Art
In association with recent progress of miniaturization, thinning, lighting, and multi-functionalization of electronic appliances, the mainstream of semiconductor device implementation technology has been being transferred from conventional package type implementation to flip chip implementation which is implementation in a unit of a bear chip or a CSP to a circuit board or the like. Such implementation is under examination in semiconductor imaging devices.
For example, the following technique was proposed as a structure and a manufacturing method thereof for attaining a lightweight semiconductor imaging device at low cost.
First, a cap glass is attached to a substrate so as to cover an imaging element section of each chip in the form of a wafer. Wherein, an attached part of the cap glass is set so as not to overlap with an imaging region on the substrate. Then, the semiconductor imaging element array in which semiconductor imaging elements are formed is diced and separated into individual pieces. The resultant semiconductor imaging element is die-bonded using an adhesive to adhere and be fixed at the bottom of a packaging box. Then, an electrode terminal of the semiconductor imaging element is connected to a terminal of a package by means of a metal wire in a wire bonding process. Thus, the semiconductor imaging device is manufactured (see Japanese Patent Application Laid Open Publication No. 03-151666A, for example).
In the above conventional example, the cap glass covers the imaging region of the semiconductor imaging element at the initial stage of the assembly, preventing the imaging region from damage of a flaw and the like and preventing deficiency which would be caused due to dust adhesion or the like in the assembly process thereafter. Further, in the above conventional example, the cap glass is attached to only a semiconductor imaging element accepted in a test carried out at the stage of the semiconductor imaging element array. This reduces assembly cost.
Another structure of a semiconductor imaging device of thin type was proposed which can be manufactured at low cost. This structure is composed of a semiconductor imaging element including an imaging region formed on a semiconductor substrate, a plurality of micro lenses, a plurality of electrode terminals, and a peripheral circuit region and a transparent plate on the semiconductor imaging element which adheres to the micro lenses by means of an adhesive having a low refractive index (see Japanese Patent Application Laid Open Publication No. 2003-031782A, for example)